Silica Gel Blue semi-transparent glassy substance containing an indicator as Cobalt Chloride a heavy metal salt. When free from moisture the Granules or beads are dark blue in colour. As the beads take up moisture, they turn to light blue gradually & When they turn pink, When the gel has absorbed approximately 8 % percent of its weight in water the coloured crystals will turn from blue to pink making an easy visual indicator of whether the gel has become saturated with moisture. It indicates that the gel needs to be replaced or regenerated. The indicating silica gel will still adsorb up to 40% of its weight in water vapour just like the non-indicating In fact, it is mainly used as an indicator for the extent of dehumidification and moisture absorption in the sealed vessel and Silica Gel Breather Industry. Blue Silica Gel is also known as Indicating Silica Gel, Self Indicating Silica Gel, Blue Desiccants, Moisture Absorber.